Re: Radial or Bias Ply Tires???

Posted by BH On 2010/10/7 9:41:51

That radial tires can only be used on a car with "Radial Tuned Suspension" is hogwash. "Radial Tuned Suspension" was simply a marketing term introduced by GM back in the early 1970s. Radial tires were actually introduced in the US market several years before that.

As the webpage cited by HH56 indicates, "Radial Tuned Suspension" simply refers to a (then) new performance suspension package that included matched front/rear sway bars, Pliacell (gas-charged) shocks, wider wheels with 70-series radial tires, and different alignment settings.

Most of the features in that package are simply add-ons that take advantage of the characteristics of radial tires.

However, I would agree that radial tires installed on a vehicle that was previously fitted with bias-ply tires require less toe-in - to decrease oversteer - as radials are more sensitive to toe.

Yet, because our Packards weren't originally fitted with "safety rims", I would NOT encourage stunt driving or performance competition with radials mounted on the OE rims.